Sleeping Rosetta spacecraft wakes up for comet rendezvous

But there was no need to ever find ourselves in this situation, nor to have missed out on the past seven months of studying the comet. The panacea? A tiny bit of Plutonium-238, whose radioactive decay could have powered the lander without the need for everything to have worked perfectly in order to generate success.

Plutonium-238 isn’t naturally occurring, but is a waste product of producing the fissionable nuclear material for use in nuclear warheads. When we bind it to two oxygen atoms — creating Plutonium dioxide — we get a tremendously stable, safe, solid configuration that emits heat, usable power, and is completely insoluble in water. This means that even if there’s a disaster on launch, the radioactive material won’t go anywhere, and can not only be retrieved, but reused in future missions.

Plutonium-238 has a half-life of 88 years, and for a mass of less than 1 kg of plutonium (and about another 12 kg of materials), you can generate 40 Watts of continuous power for the entire duration of the mission, plus enough excess heat to keep the electronics warm. (Above, you can see the Plutonium pellet glowing from its own heat.) Considering that the entire solar panel assembly for Philae was 12.2 kg and generated about 32 Watts while in direct sunlight at a distance of 3 AU from the Sun, there’s no scientific reason not to use it.

Except for two pesky facts that we, as humans, could do something about.

All previous deep space probes have used RTGs [Radio-isotope Thermoelectric Generator], but the ESA has not developed RTG technology. They couldn’t get it from NASA (who wouldn’t provide it) or Roscosmos (which would violate the ITAR treaty).
We are literally running out of our Pu-238 supply for deep space missions. We are no longer making more, although we could be easily doing so for scientific purposes. It just costs a little bit of money.
In fact, if we only wanted to use a tiny amount of Pu-238 to keep the electronics warm, we could have done exactly that — with the same solar technology — with an expenditure of only two grams of Pu-238. This is the strategy that Mars Opportunity employed, and it’s been roving on Mars successfully (and continuously) for over a decade now. In fact, Stephan Ulamec, project manager of the Philae lander, has openly said the reason they didn’t use this material is for political reasons. And as a result, we missed seven months of learning about the comet’s surface, interior and all the changes that occurred while it came alive.

I read that "Rosetta was going to join Philae on the surface" by the end of the year.

Does that mean that they are going to try to land Rosetta on the comet, or just crash it and see what kind of dust it kicks up?

One year ago, Andrea Accomazzo and his team made space history. He tells DW why the Rosetta spacecraft, in spite of being in the wrong location when it dropped Philae, was a spectacular achievement.

The researchers behind the Rosetta space probe has said they have found some of the essential building blocks of life. The discovery could be a game-changer in the debate over how living organisms developed on Earth.

The European Space Agency’s Rosetta mission is about to come to a dramatic end. It has spent years successfully gathering data on 67P, a comet 317 million miles away from Earth that scientists hope may contain clues on the creation of the universe. This week it will be set on a collision course with the comet to end the mission